periodical 音标拼音: [p
, ɪri'ɑdɪkəl]
n . 期刊
a . 周期的,定期的
期刊周期的,定期的
periodical 周期
periodical adj 1 :
happening or recurring at regular intervals ; "
the periodic appearance of the seventeen -
year locust " [
synonym :
{
periodic }, {
periodical }] [
ant : {
aperiodic },
{
nonperiodic }]
n 1 :
a publication that appears at fixed intervals Periodic \
Pe `
ri *
od "
ic \ (
p [=
e ]`
r [
i ^]*[
o ^]
d "[
i ^]
k ),
Periodical \
Pe `
ri *
od "
ic *
al \ (
p [=
e ]`
r [
i ^]*[
o ^]
d "[
i ^]*
kal ),
a . [
L .
periodicus ,
Gr .
periodiko `
s :
cf .
F .
p ['
e ]
riodique .]
1 .
Of or pertaining to a period or periods ,
or to division by periods .
[
1913 Webster ]
The periodical times of all the satellites . --
Sir J .
Herschel .
[
1913 Webster ]
2 .
Performed in a period ,
or regular revolution ;
proceeding in a series of successive circuits ;
as ,
the periodical motion of the planets round the sun .
[
1913 Webster ]
3 .
Happening ,
by revolution ,
at a stated time ;
returning regularly ,
after a certain period of time .
[
1913 Webster ]
The periodic return of a plant '
s flowering .
--
Henslow .
[
1913 Webster ]
To influence opinion through the periodical press .
--
Courthope .
[
1913 Webster ]
4 .
Acting ,
happening ,
or appearing ,
at fixed or somewhat variable intervals ;
recurring ;
as ,
periodical epidemics [
1913 Webster ]
5 . (
Rhet .)
Of or pertaining to a period ;
constituting a complete sentence .
[
1913 Webster ]
{
Periodic comet } (
Astron .),
a comet that moves about the sun in an elliptic orbit ;
a comet that has been seen at two of its approaches to the sun .
{
Periodic function } (
Math .),
a function whose values recur at fixed intervals as the variable uniformly increases .
The trigonomertic functions ,
as sin (
x ),
tan (
x ),
etc .,
are periodic functions .
Exponential functions are also periodic ,
having an imaginary period ,
and the elliptic functions have not only a real but an imaginary period ,
and are hence called doubly periodic .
{
Periodic law } (
Chem .),
the generalization that the properties of the chemical elements are periodic functions of their atomic weights . "
In other words ,
if the elements are grouped in the order of their atomic weights ,
it will be found that nearly the same properties recur periodically throughout the entire series ."
The following tabular arrangement of the atomic weights shows the regular recurrence of groups (
under I .,
II .,
III .,
IV .,
etc .),
each consisting of members of the same natural family .
The gaps in the table indicate the probable existence of unknown elements .
{
Periodic table }, {
Periodic table of the elements } (
Chem .),
A tabular arrangement of the chemical elements ,
illustrating the {
periodic law },
described above .
[
1913 Webster ]
Note :
Note :
A modern version of the periodic table can be found at :
http ://
pearl1 .
lanl .
gov /
periodic /
default .
htm [
PJC ]
TABLE OF THE PERIODIC LAW OF THE CHEMICAL ELEMENTS (
The vertical columns contain the periodic groups )
Series1 [
2 [
3 [
4 [
5 [
6 [
7 [
8 [
9 [
10 [
11 [
12 [
--------------------------------------------------------------
|
I .
II .
III .
IV .
V .
VI .
VII .
VIII . |
RH4 RH3 RH3 RH |
R2O RO R3O3 RO2 R2O5 RO3 R2O7 RO4 --------------------------------------------------------------
H 1 Li 7 Na 23 K 39 (
Cu )
63 Rb 85 .
2 (
Ag )
(
108 )
Cs 133 (-)
(-)
(
Au )
(
197 )
---------------------------------------------------------------
[
1913 Webster ]
Note :
A similar relation had been enunciated in a crude way by Newlands ;
but the law in its effective form was developed and elaborated by Mendelejeff ,
whence it is sometimes called {
Mendelejeff '
s law }.
Important extensions of it were also made by L .
Meyer .
By this means Mendelejeff predicted with remarkable accuracy the hypothetical elements ekaboron ,
ekaluminium ,
and ekasilicon ,
afterwards discovered and named respectively scandium ,
gallium ,
and germanium .
[
1913 Webster ]
{
Periodic star } (
Astron .),
a variable star whose changes of brightness recur at fixed periods .
{
Periodic time of a heavenly body } (
Astron .),
the time of a complete revolution of the body about the sun ,
or of a satellite about its primary .
[
1913 Webster ]
Periodical \
Pe `
ri *
od "
ic *
al \,
n .
A magazine or other publication which appears at stated or regular intervals .
[
1913 Webster ]
55 Moby Thesaurus words for "
periodical ":
airing ,
almanac ,
alternate ,
annual ,
bandying ,
bimonthly ,
biweekly ,
book ,
broadcast ,
broadcasting ,
bruiting ,
bruiting about ,
circulation ,
daily ,
daybook ,
diary ,
diffusion ,
display ,
dissemination ,
ephemeris ,
evulgation ,
fortnightly ,
gazette ,
hebdomadal ,
isochronal ,
issuance ,
issue ,
journal ,
magazine ,
monthly ,
newsletter ,
newsmagazine ,
newspaper ,
organ ,
paper ,
pictorial ,
printing ,
promulgation ,
propagation ,
publication ,
publishing ,
quarterly ,
recurring ,
renew ,
review ,
serial ,
slick magazine ,
spread ,
spreading ,
spreading abroad ,
telecasting ,
trade magazine ,
ventilation ,
weekly ,
yearbook
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